Crown 460CSL Manual De Usuario
Power Base-1 & 460CSL Amplifier Service Manual
14
TEST 4: AC POWER DRAW
Spec: 90 Watts maximum quiescent.
Initial Conditions: Controls per standard.
Procedure: With no input signal and no load, measure
AC line wattage draw. If current draw is excessive,
check for high AC line voltage or high bias voltage.
check for high AC line voltage or high bias voltage.
TEST 5: COMMON MODE REJECTION
Spec at 100 Hz: –70 dB.
Spec at 20 kHz: –50 dB.
Initial Conditions: Controls per standard.
Procedure: No load. Inject a 0 dBu 100 Hz sine wave
into each channel, one channel at a time, with inverting
and non-inverting inputs shorted together. At the
output measure less than –44 dBu. Inject a 0 dBu 20
kHz sine wave into each channel, one channel at a
time, with inverting and non-inverting inputs shorted
together. At the output measure less than –24 dBu.
Adjust R921 or R1021, if necessary, to obtain the
required measurements. (In older units the adjust-
ments are done using N100/N200.)
and non-inverting inputs shorted together. At the
output measure less than –44 dBu. Inject a 0 dBu 20
kHz sine wave into each channel, one channel at a
time, with inverting and non-inverting inputs shorted
together. At the output measure less than –24 dBu.
Adjust R921 or R1021, if necessary, to obtain the
required measurements. (In older units the adjust-
ments are done using N100/N200.)
TEST 6: VOLTAGE GAIN
Spec: ±3% when the Sensitivity Switch is set for 26dB
gain, ±6% when the Sensitivity Switch is set for 0.775V
or 1.4V sensitivity.
Initial Conditions: Controls per standard.
or 1.4V sensitivity.
Initial Conditions: Controls per standard.
Procedure: No load connected. Inject a 0.775 VAC 1
kHz sine wave with the Sensitivity Switch in the 26 dB
position. Measure 15.5 VAC ±0.07 VAC at the ampli-
fier output. Inject a 0.775 VAC 1 kHz sine wave with the
Sensitivity Switch in the 0.775V position. Measure 39.9
VAC ±1.2 VAC at the amplifier output. Inject a 1.4 VAC
1 kHz sine wave with the Sensitivity Switch in the 1.4V
position. Measure 39.9 VAC ±1.2 VAC at the amplifier
output. Return the Sensitivity Switch to the 26 dB
position.
position. Measure 15.5 VAC ±0.07 VAC at the ampli-
fier output. Inject a 0.775 VAC 1 kHz sine wave with the
Sensitivity Switch in the 0.775V position. Measure 39.9
VAC ±1.2 VAC at the amplifier output. Inject a 1.4 VAC
1 kHz sine wave with the Sensitivity Switch in the 1.4V
position. Measure 39.9 VAC ±1.2 VAC at the amplifier
output. Return the Sensitivity Switch to the 26 dB
position.
TEST 7: PHASE RESPONSE
Spec: ±10° at 1 Watt.
Initial Conditions: Controls per standard, 8 ohm load on
each channel.
Procedure: Inject a 1 kHz sine wave and adjust for 1
Procedure: Inject a 1 kHz sine wave and adjust for 1
Watt output (2.8 VAC). Check input and output signals
against each other, input and output signals must be
within 10° of each other.
against each other, input and output signals must be
within 10° of each other.
TEST 8: LEVEL CONTROLS
Spec: Level controlled by level controls.
Initial Conditions: Controls per standard.
Checkout Procedures
Procedure: No Load. Inject a 1 kHz sine wave. With
level controls fully clockwise you should see full gain.
As controls are rotated counterclockwise, observe
similar gain reduction in each channel. When com-
plete, return level controls to fully clockwise position.
As controls are rotated counterclockwise, observe
similar gain reduction in each channel. When com-
plete, return level controls to fully clockwise position.
TEST 9: CURRENT LIMIT
Spec: Current Limit at 13 ±2 Amps
Initial Conditions: Controls per standard.
Procedure: Load each channel to 1 Ohm. Inject a 1 kHz
differentiated (or 10% duty cycle) square wave and
increase output level until current limit occurs. Current
limit should occur at 11 ±1 Amps. Observe clean (no
oscillations) current clipping.
increase output level until current limit occurs. Current
limit should occur at 11 ±1 Amps. Observe clean (no
oscillations) current clipping.
TEST 10: SLEW RATE & 10 KHZ SQUARE WAVE
Spec: >13V/µS.
Initial Conditions: Controls per standard.
Procedure: Load each channel to 8 ohms. Inject a 10
kHz square wave to obtain 40 volts peak-to-peak at
each output. Observe the slope of the square wave. It
should typically measure 17 to 25 V/µS. Also, the
square wave must not include overshoot, ringing, or
any type of oscillation.
each output. Observe the slope of the square wave. It
should typically measure 17 to 25 V/µS. Also, the
square wave must not include overshoot, ringing, or
any type of oscillation.
TEST 11: CROSSTALK
Spec: <33 mVAC at 20 kHz.
Initial Conditions: Controls per standard. Short input of
channel not driven.
Procedure: 8 ohm load on each channel. Inject a 20 kHz
Procedure: 8 ohm load on each channel. Inject a 20 kHz
sine wave into the Channel 1 input and increase output
level to 37.4 VAC. Measure less than 33 mVAC at the
output of Channel 2. Inject a 20 kHz sine wave into the
Channel 2 input and increase output level to 37.4 VAC.
Measure less than 33 mVAC at the output of Channel
1.
level to 37.4 VAC. Measure less than 33 mVAC at the
output of Channel 2. Inject a 20 kHz sine wave into the
Channel 2 input and increase output level to 37.4 VAC.
Measure less than 33 mVAC at the output of Channel
1.
TEST 12: OUTPUT POWER
Spec at 8 Ohm Stereo: 205W at 0.1% THD.
Spec at 4 Ohm Stereo: 230W at 0.1% THD.
Initial Conditions: Controls per standard.
Procedure: Load each channel to 8 ohms. Inject a 1 kHz
sine wave and measure at least 40.5 VAC at the output
of each channel. Load each channel to 4 ohms. Inject
a 1 kHz sine wave and measure at least 30.3 VAC. All
power measurements must be at less than 0.1% THD.
of each channel. Load each channel to 4 ohms. Inject
a 1 kHz sine wave and measure at least 30.3 VAC. All
power measurements must be at less than 0.1% THD.
TEST 13: REACTIVE LOADS
Spec: No oscillations. Safe with all types of loads.
Initial Conditions: Controls per standard.